<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2012 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------

defined('THINK_PATH') or exit();
/**
 * 文件类型缓存类
 * @category   Think
 * @package  Think
 * @subpackage  Driver.Cache
 * @author    liu21st <liu21st@gmail.com>
 */
class CacheFile extends Cache {

	/**
	 * 架构函数
	 * @access public
	 */
	public function __construct($options=array()) {
		if(!empty($options)) {
			$this->options =  $options;
		}
		$this->options['temp']      =   !empty($options['temp'])?   $options['temp']    :   C('DATA_CACHE_PATH');
		$this->options['prefix']    =   isset($options['prefix'])?  $options['prefix']  :   C('DATA_CACHE_PREFIX');
		$this->options['expire']    =   isset($options['expire'])?  $options['expire']  :   C('DATA_CACHE_TIME');
		$this->options['length']    =   isset($options['length'])?  $options['length']  :   0;
		if(substr($this->options['temp'], -1) != '/')    $this->options['temp'] .= '/';
		$this->init();
	}

	/**
	 * 初始化检查
	 * @access private
	 * @return boolen
	 */
	private function init() {
		$stat = stat($this->options['temp']);
		$dir_perms = $stat['mode'] & 0007777; // Get the permission bits.
		$file_perms = $dir_perms & 0000666; // Remove execute bits for files.

		// 创建项目缓存目录
		if (!is_dir($this->options['temp'])) {
			if (!  mkdir($this->options['temp']))
			return false;
			chmod($this->options['temp'], $dir_perms);
		}
	}

	/**
	 * 取得变量的存储文件名
	 * @access private
	 * @param string $name 缓存变量名
	 * @return string
	 */
	private function filename($name) {
		$name	=	md5($name);
		if(C('DATA_CACHE_SUBDIR')) {
			// 使用子目录
			$dir   ='';
			for($i=0;$i<C('DATA_PATH_LEVEL');$i++) {
				$dir	.=	$name{$i}.'/';
			}
			if(!is_dir($this->options['temp'].$dir)) {
				mkdir($this->options['temp'].$dir,0755,true);
			}
			$filename	=	$dir.$this->options['prefix'].$name.'.php';
		}else{
			$filename	=	$this->options['prefix'].$name.'.php';
		}
		return $this->options['temp'].$filename;
	}

	/**
	 * 读取缓存
	 * @access public
	 * @param string $name 缓存变量名
	 * @return mixed
	 */
	public function get($name) {
		$filename   =   $this->filename($name);
		if (!is_file($filename)) {
			return false;
		}
		N('cache_read',1);
		$content    =   file_get_contents($filename);
		if( false !== $content) {
			$expire  =  (int)substr($content,8, 12);
			if($expire != 0 && time() > filemtime($filename) + $expire) {
				//缓存过期删除缓存文件
				unlink($filename);
				return false;
			}
			if(C('DATA_CACHE_CHECK')) {//开启数据校验
				$check  =  substr($content,20, 32);
				$content   =  substr($content,52, -3);
				if($check != md5($content)) {//校验错误
					return false;
				}
			}else {
				$content   =  substr($content,20, -3);
			}
			if(C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {
				//启用数据压缩
				$content   =   gzuncompress($content);
			}
			$content    =   unserialize($content);
			return $content;
		}
		else {
			return false;
		}
	}

	/**
	 * 写入缓存
	 * @access public
	 * @param string $name 缓存变量名
	 * @param mixed $value  存储数据
	 * @param int $expire  有效时间 0为永久
	 * @return boolen
	 */
	public function set($name,$value,$expire=null) {
		N('cache_write',1);
		if(is_null($expire)) {
			$expire =  $this->options['expire'];
		}
		$filename   =   $this->filename($name);
		$data   =   serialize($value);
		if( C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {
			//数据压缩
			$data   =   gzcompress($data,3);
		}
		if(C('DATA_CACHE_CHECK')) {//开启数据校验
			$check  =  md5($data);
		}else {
			$check  =  '';
		}
		$data    = "<?php\n//".sprintf('%012d',$expire).$check.$data."\n?>";
		$result  =   file_put_contents($filename,$data);
		if($result) {
			if($this->options['length']>0) {
				// 记录缓存队列
				$this->queue($name);
			}
			clearstatcache();
			return true;
		}else {
			return false;
		}
	}

	/**
	 * 删除缓存
	 * @access public
	 * @param string $name 缓存变量名
	 * @return boolen
	 */
	public function rm($name) {
		return unlink($this->filename($name));
	}

	/**
	 * 清除缓存
	 * @access public
	 * @param string $name 缓存变量名
	 * @return boolen
	 */
	public function clear() {
		$path   =  $this->options['temp'];
		if ( $dir = opendir( $path ) ) {
			while ( $file = readdir( $dir ) ) {
				$check = is_dir( $file );
				if ( !$check )
				unlink( $path . $file );
			}
			closedir( $dir );
			return true;
		}
	}
}